Google's Sitemap Tool Showing Random Pages in Highest PageRank Stat

In Google Sitemaps there is a statistic under stats/ crawl statistics that shows you "Your page with the highest PageRank." It looks like this for this site:

Now, several people are reporting that they have heard of or seen themselves, random pages being displayed in that report.

I suddenly see a change in my highest PR page as reported by Google Webmaster Tools. It used to be the homepage, obviously, until October 2006.
One both months - October and November the pages shown as highest PR are what seems to be just random internal pages. The homepage is PR4 (down from long time PR5) and the October page is only PR1 and November page does not even have any PR at all according to the Toolbar.

For one of my verified sites, the report does not show at all. But for all the others, it seems like it works just fine.

Maybe this is showing a different, more current, PageRank value? I really do not know for sure.